Seth Martinez would be a leverage reliever for several teams. He’s a roster-crunch casualty in Houston

Baseball is a notoriously unfair game on the field. It can be off of it as well.

Few players better understand that sentiment right now than Seth Martinez, who was optioned to Triple-A Sugar Land on Saturday when the Astros activated Lance McCullers Jr. from the injured list.

Martinez, a 27-year-old rookie, has a 2.48 ERA (2.83 xERA) across 32 ²⁄₃ innings. Now he’s back in the minors.

It’s a move that needed to be made but is nevertheless cutthroat for Martinez, who had proven to be an effective arm in a bullpen that has the lowest ERA in baseball.

A 17th-round pick out of Arizona State in the 2016 draft, Martinez had grinded his way through the minor leagues for six years before finally getting the chance to establish himself as a viable big leaguer in 2022. He’s done that and then some.

In his 30-plus innings of work, Martinez has yielded a .179 batting average against. It’s tied with Cristian Javier for the lowest BAA on the Astros pitching staff. His .197 xBA trails only Javier.

Armed with a deceptive four-seam fastball and a sweeping slider, Martinez attacked hitters early and pitched with tempo. No other Astros pitcher has gotten to 0-1 in the count as frequently as Martinez has, nor has any other operated as quickly.

It’s not premium velocity or a wicked breaking ball that’s stymied opposing hitters, it’s Martinez’s ability to induce weak contact while missing an adequate number of bats in the process. Though his fastball averages 92 mph, its Perceived Velocity is roughly one tick higher. Only Phil Maton has a greater positive difference among Astros hurlers.

It’s that type of deception that’s helped generate a well-rounded profile in terms of exit velocity and launch angle. Martinez has not only avoided barrels, he’s routinely caused hitters to produce the least effective kind of batted ball: pop-ups. The rookie righty owns the highest pop-up rate on the Astros and ranks 15th among all pitchers (min. 50 pitches).

Martinez has also fared well on the opposite end of the launch-angle spectrum, as his third offering, a sinker, generates a fair amount of ground balls. Combining pop-ups and ground balls, only Framber Valdez, Bryan Abreu and Rafael Montero induce them at a higher rate.

Martinez isn’t a strikeout fiend or a command artist — he’s middling in both the strikeout and walk departments — but he’s displayed real talent when it comes to pitching to contact, something that is quite notable in an era that values pitchers with optimal batted-ball profiles.

In a relief corps that is one of the best in the big leagues, Martinez seldom found himself pitching in key situations. He ranks last among Astros relievers in terms of FanGraphs’ Average Leverage Index. As a rookie in a fairly loaded bullpen, it’s to be expected. He could only control how well he pitched when called upon, and he did.

In a number of other bullpens, Martinez would likely be a late-inning option. But for the Astros, for the time being, he is a minor-league reliever.